This live CD is customized by roughly following the guidelines at:
  https://help.ubuntu.com/community/LiveCDCustomization
  https://help.ubuntu.com/community/LiveCDCustomizationFromScratch
  https://help.ubuntu.com/community/MakeALiveCD/DVD/BootableFlashFromHarddiskInstall
plus a lot of other info, like ubiquity and casper source code, and
additions for making the resulting iso EFI bootable.

extractiso.sh
  extract the original iso

customize.sh
  apply customizations

enter.sh
  chroot into the install (for optional manual customization)

buildiso.sh
  build the new iso

run.sh -c
  boot the iso in qemu with a blank hdd, to test the install

run.sh -d
  boot the installed hdd in qemu

cleanup.sh
  remove everything but the isos


SHORT VERSION:
  sudo apt-get install squashfs-tools xorriso isolinux systemd-container
  time sudo sh -c "env BUILD_CONFIG=12.10 ./full-rebuild.sh"
  time sudo sh -c "env BUILD_CONFIG=13.04 ./full-rebuild.sh"